4.2.2: Classification and evolution

Question 1

Classification

Answer 1

Putting living things into groups with other organisms that share similar characteristics.

Question 2

Number and names of historic taxonomic groups:

Answer 2

7 groups
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 3

Current taxonomic groups

Answer 3

• Domain
• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Question 4

Phylogeny

Answer 4

the study of evolutionary relationships between species.

Question 5

Traditional classification kingdoms

Answer 5

Prokaryotae, protoctista, plantae, fungi, animalia

Question 6

3 domains

Answer 6

• Bacteria
• Archaea
• Eukaryotae

Question 7

Kingdoms of modern classification (x6)

Answer 7

• Eubacteria
• Archaebacteria
• Protoctista
• Plantae
• Fungi
• Animalia

Question 8

Why scientists classify organisms

Answer 8

• To identify species
• To predict characteristics
• To find evolutionary links

Question 9

Eubacteria (kingdom)

Answer 9

• Unicelluar
• No nucleus (prokaryotic)
• No membrane-bound organelles
• Carry out respiration on meso

Question 10

Eubacteria (kingdom)

Answer 10

• Unicelluar
• No nucleus (prokaryotic)
• No membrane-bound organelles
• Carry out respiration on mesosomes
• Smaller ribosomes (70s) than other organisms

Question 11

Mesosome

Answer 11

Folding in the cell surface membrane

Question 12

Archaebacteria (kingdom)

Answer 12

• Unicellular, no nucleus or membrane-bound organelles
• Virtually unchanged since they evolved –> ancient
• Can survive in extreme environments e.g. hot thermal vents or acidic/anaerobic conditions

Question 13

Protoctista (kingdom)

Answer 13

• Eukaryotic
• Mostly single-celled
• Mostly free living (don’t live within other organisms)
• Can be autotrophs or heterotrophs
• Some have chloroplasts
• “Dustbin kingdom”

Question 14

Plantae (kingdom)

Answer 14

• Multicellular eukaryotes
• Autotrophs (because of photosynthesis)
• Contain chlorophyll
• Cellulose cell wall
• Store glucose as starch
• Can reproduce sexually or asexually (some)

Question 15

Fungi (kingdom)

Answer 15

• Heterotrophic eukaryotes
• Unicellular (yeast) or multicellular (mushrooms)
• Chitin cell wall
• Reproduce using spores
• Saprophytic (secrete enzymes)
• Store glucose as glycogen
• No chloroplasts
• Consist of a mycelium (network of multinucleate hyphae)

Question 16

Animalia (kingdom)

Answer 16

• Multicellular eukaryotes
• Heterotrophic
• No cell wall
• Fertilised egg develops into blastula
• Usually able to move
• Store glucose as glycogen

Question 17

Chordata

Answer 17

Name of phylum; mostly vertebrates

Question 18

Common ancestor

Answer 18

Organism from which two organisms evolved.

Question 19

Advantages of phylogenetic classification

Answer 19

✔︎ Produces a continuous tree; scientists are not forced to place organisms into categories they don’t properly fit into
✔︎ Linnean classification implies different groups with the same rank are equivalent; in reality some have much longer histories (compare cats, short, and orchids, long,) and are much more diverse (30 cat species, 20,000 orchid species)

Question 20

Natural selection

Answer 20

“survival of the fittest”; the best adapted to a given environment survive and reproduce; governed by nature, takes millions of years.

Question 21

Artificial selection

Answer 21

breeding animals specifically for certain characteristics; governed by humans and takes centuries.

Question 22

Convergent evolution

Answer 22

some features are so useful that they will develop independently of one another.

Question 23

Reasons for gaps in the fossil record

Answer 23

• Fossils can be destroyed
• Fossils may not have been discovered
• Fossils are only formed under certain conditions
• Soft bodied organisms may decay before fossils can form

Question 24

Why are fossils useful?

Answer 24

• Shows how organisms have changed over time (different layer of rock corresponds to different geological era)
• Shows relationships between extinct and extant organisms

Question 25

Comparative anatomy

Answer 25

• Gives evidence for divergent evolution | ⟶ Common ancestor from which different species have evolved, occurs when organisms have adapted to new habitats

Question 26

How evolution works (Model answer)

Answer 26

1) VARIATION caused by genetic MUTATION 2) Environmental selection of advantageous variations (SELECTION PRESSURE) 3) SURVIVAL OF THE FITTEST 4) Reproduction to pass on advantageous characteristics in the form of ALLELES 5) ADAPTATION: next generation better suited to their environment.

Question 27

Methods by which bacteria become resistant to antibiotics

Answer 27

* Build protein that forms efflux pump * Code for antibiotic degrading enzyme * Code for antibiotic-altering enzyme

Question 28

Types of variation

Answer 28

* Interspecific (between species) | * Intraspecific (within a species)

Question 29

Reasons for increased antibiotic resistance

Answer 29

* Failure to finish a course of antibiotics | * Overuse or incorrect use of antibiotics

Question 30

Two possible causes of variation

Answer 30

* Genotype (genetic causes) | * Environmental factors

Question 31

Environmental causes of variation (examples)

Answer 31

* Plant height (depends on nutrients/light) * Hydrangea colour (dependent on pH of soil) * Human scars (although how the wound heals may be partially genetically determined)

Question 32

Genetic causes of variation

Answer 32

* Different alleles * Mutations (change in DNA sequence alters alleles) * Meiosis (independent assortment m1, crossing over p1, random orientation m2) * Sexual reproduction (random selection of gametes, combination of alleles from 2 parents)

Question 33

Genetic causes of variation (examples)

Answer 33

* Natural eye colour | * Blood type

Question 34

Variation determined by environmental and genetic factors (examples)

Answer 34

* Human height (max. potential = genetic, malnourishment may reduce) * Skin colour (alleles + sun exposure)

Question 35

Continuous variation

Answer 35

* No distinct categories * Tends to be quantitative * Controlled by genetic factors * Influenced by environment

Question 36

Discontinuous/discreet variation

Answer 36

* Distinct categories * Tends to be qualitative * Controlled by a few genes * Unaffected by the environment

Question 37

Polygenic inheritance

Answer 37

inheritance of a characteristic controlled by many genes which are often located on different chromosomes.

Question 38

Example of polygenic inheritance

Answer 38

Skin tone; controlled by 8 genes

Question 39

Standard deviation shows

Answer 39

How much variation there is between the data and the mean. A measure of the spread of the data.

Question 40

Spearman's rank correlation coefficient

Answer 40

Determines the strength of a correlation between two variables.